Method of making heat exchangers



mm 5 mm J. R. HAYWARD $0 3 METHOD OF MAKING HEAT EXCHANGEZRS Filed Jan, 2, 1948 2 Sheets-Sheet l MEL INVENTOR.

l9 [9 JAMES R. HAYWARD ajw :4 TTOR/VEV @@@a Wm J. m. HAYWARD METHOD OF meme HEAT EXCHANGERS 2 Sheets-Sheet 2 Filewd Jam. 2, 1948 INVENTOR. JAMES R. HAYWARD Pltentell Dec. 5; 1950 UNITED; STATES PATENT OFFICE METHOD OF MAKING HEAT EXCHANGEBS James R. Hayward, Washington, Ind., assignor to McCoi-d Corporation ration of Maine Detroit, Mich, a corpo- Application January 2, 194a, serial No. 307

scum. (01. 113-118) fins are secured upon the tubes by flanges projecting in the same direction from each of the fins and which flanges extend around the circumference of the tubes and into tube slots by which the tubes are inserted in the fins.

Another object of the invention is to provide a method which may be employed for manufacturing such I heat exchange devices, and by which method the fins may be formed and positioned upon a heat exchange tube as a relatively continuous process. Other and further objects of the invention will be apparent by reference to the accompanying drawings of which there are two sheets,

which, by way of illustration, show a preferred embodiment and the principles thereof and what I now consider to be the best mode in which I have contemplated applying these principles. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims. I also contemplate that of the several different features of my invention, certain ones thereof may be advantageously employed in some applications separate and apart from the remainder of the features.

In the drawings:

Fig. 1 illustrates a side elevational view of a heat exchange device embracing the principles of the invention.

Fig. 2 is a plan view of the heat exchange device discloaed by Fig. 1.

Fig. 3 is a fragmentary enlarged cross sectional view of the heat exchange device illustrated by Figs. 1 and 2. Fig. 3 is taken in the plane of line H on Fig. 2 looking in the direction of the arrows.

Fig. 4 is a plan view of a sheet of metal from which heat exchange fins are being formed and placed upon a plurality of tube sections to form a heat exchange device embracing the principles of this invention.

the structure and the process being practiced in Fig. 4. Fig. 5 is taken in the plane of line 5-5 on Fig. 4 looking in the direction of the arrows. Referring particularly to Figs. 1, 2. and 3, the

I numeral l0 indicates generally a heat exchange device embracing the principles of the invention and comprising essentially a continuous heat exchange tube Ii upon which heat exchange fins H are equally spaced. The tube H has return 10 bends l3 formed therein in equally spaced relation to one another so as to provide between the return bends a plurality of equally spaced and parallel tube sections II. The fins l2 are positioned upon the tube sections 14 in spaced rela- 18 tion to one another and in such manner as to completely occupy the space between the return bends l3.

The fins l2 are formed with tube slots I9 projecting therein in equally spaced relation. Along 00 one edge of each fin the tube sections it are disposed within the rear portions of the tube slots l9 and are secured therein by flanges i1 formed integrally with respect to the fins II. The flanges il extend practically all the way as around the tube sections it, the ends of the flanges I'I projecting into the tube slots l9 and terminating therein adjacent one another.

The heat exchange device illustrated by Figs. 1, 2, and 3 may be constructed by the process 80 illustrated by Figs. 4 and 5.

The process illustrated by Figs. 4 and 5 comprises three principal steps, although it will be apparent from a description of the process that these steps do not have to be performed as illus- 35 trated but maybe divided in such a way as to provide a greater number of steps or may be combined and performed as a lesser number of steps.

In Figs. 4 and 5 the numeral I8 indicates a 4n sheet of tin stock being processed in such manner as to produce the fins l2 employed in the condenser III. In practicing the process the sheet I8 is punched at work station 22 so as to provide a plurality of tube slots l9 extending I transversely across the sheet l8 in equally spaced to station to another.

The tube slots I 9 consist of front relatively rectangularly formed portions 23 and rear portions 2| which are narrower than the front portions by distances equal to the height which Fig. 5 is averticalsectional view illustrating 05 maybe desired to make the flanges I] for en- 3 gaging the tube sections II. The rear portions 24 of the openings It at one end thereof are formed about centers 26 which later become the tube opening centers on which the tube sections H are located. 1

Extending rearwardly from the sides of each of the tube slots I! are tool marks or slits indicated at 21 which terminate directly oppositely with respect to the centers 26. The tool marks 21 may extend entirely through the fin stock I8 to provide slits, or may merely mark the surface of the fin stock in such manner that later it may be sheared more easily when the flanges 11 are formed about the tube sections ll.

It will be apparent that the tube slots l9 and the marks 21 may be formed as a single operation at work station 22, or may be formed by performing a greater number of operations at a greater number of work stations.

After the formation of the tube slots 19 across the sheet 18, the sheet 18 may be moved in such manner as to bring all of the tube slots I 9 to work station 28 where flanges I1 are formed around the rear portions of the tube slots 19 by projecting laterally in one direction the material around the rear portions of the slots l9 and about the centers 26. The flanges i1 when formed at work station 28 comprise U-shaped -fianges having bends 29 at the rear ends thereof and legs 3i projecting forwardly of the bends 29 along the sides of the slots [9. The stock 48 may also be cut off at work station 28 as is indicated at 32. The cuts 32 are made transversely across the sheet l8 between the front portions 23 of the tube slots Hi just back of the front ends 2| and between such portions of certain tube slots and the edges of the fin stock 18.

During the time that the flange i1 is being formed at station 28 and the cut oil 32 is being made at station 28, another series of tube slots [9 may be formed simultaneously therewith at work station 22,

When the stock l8 thereafter is moved to work station 34 a fin 12 will be formed by a repetition of the operations performed at work stations 22 and 28. The tube H is positioned at work stav tion 34 in such manner that the sections l4 thereof will be projected into the tube slots l9 when the stock is moved from work station 28 to work station 34.

Simultaneously with the shearing of the stock at 32 or immediately thereafter, if such is preferred, the legs 3| of the U-shaped flanges l1 are projected into the tube slots is in such manner as to extend around the front of each of the tube sections 14 with the ends of the legs 3| terminating within the tube slots and directly opposite one another. The projection of the legs 3| into the tube slots I9 is done in such manner as to cause the flanges I1 to press against the tube sections 14 from one end to the other of the flanges l1 thereby providing a close fit and good thermal contact between the inner surfaces of the flanges and the exterior surfaces of the tube sections 14.

As this flange closing operation is performed at work station 34, or thereafter if such is preferred, the tube H and fin I 2 may be indexed laterally with respect to the plane of the fin stock 18 to Work station 36 thereby providing space upon the tube sections 14 for the disposition of another fin I2 formed as previously described.

As the foregoing operations are repeated, the tube II and fins l2 will be successively moved to other work stations indicated at 31, 38, etc., until stood that this ls capable of modification, and I' therefore do not wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall within the purview of the following claims. 1 v

I claim:

1. A method of forming heat exchange devices which comprises moving a sheet of fin stock in the direction of its length, successively forming openings at longitudinally spaced points in said sheet of fin stock by removing strips of metal from said fin stock inwardly from a point corresponding to the forward edge of a fin to be formed so as to define a tube slot approximately of tube width at a front portion of said slot and of less than tube width at a rear portion of said slot, forming in the leading slot a U-shaped flange around said rear portion of said slot with the legs of said flange extending along the sides of said slot, projecting a tube within said leading slot against the bend of said flange by relative lateral movement of said fin stock and said tube, cutting a fin from said fin stock by severing said fin stock between the front end of the succeeding tube slot and the adjacent side edges of said fin stock, projecting said flange legs of said leading tube slot inwardly around the front of said tube, and indexing said tube and fin transversely out of the plane of said fin stock to provide space on said tu e for repeating the aforesaid operations.

2. A method of forming heat exchange devices which comprises forming anopening in a sheet of fin stock by removing a strip of metal from said fin stock inwardly from a point corresponding to the forward edge of a fin to be formed so as to define a tube slot approximately of tube width at a front portion of said slot and of less than tube width at a rear portion of said slot, forming a U-shaped flange around said rear portion of said slot with the legs of said flange extending along the sides of said slot, projecting a tube within said slot against the bend of said flange by relative lateral movement of said fin stock and said tube, cutting a fin from said fin stock and projecting said flange legs inwardly of said tube slot around the front of said tube, all of said operations being performed successively on one portion of said stock to form a fin and contemporaneously on successive portions of said stock to partially form a series of fins.

3. A method of forming heat exchange devices which comprises moving a sheet of fin stock in the direction of its length, successively forming openings at longitudinally spaced points in said sheet of fin stock by removing strips of metal from said fin stock inwardly from a point corresponding to the forward edge of a fin to be formed so as to define a tube slot approximately of tube width at a front portion of said slot and of less than tube width at a rear portion of said slot, forming in the leading slot a U-shaped flange around said rear portion of said slot with the legs of said flange extending along the sides of said slot, projecting a tube within said leading slot against the bend of said flange by relative lateral movement of said fin stock and said tube, and simultaneously cutting a fin from said fin stock by severing said fin stock between the front end of the succeeding tube slot and the adjacent side edges of said fin stock and projecting said flange legs of said leading tube slot inwardly aroundthe front of said tube.

4. A method of forming heat exchange devices which comprises forming an opening in a sheet of fin stock by removing a strip of metal from said fin stock inwardly from a point corresponding to the forward edge of a fin to be formed so as to define a tube slot approximately of tube width at a front portion of said slot and of less than tube width at a rear portion of said slot, forming a U-shape flange around said rear portion of said slot with the legs of said flange extending along the sides of said slot, projecting a tube within said slot against the bend of said flange by relative lateral movement of said fin stock and said tube, and simultaneously cutting a fin from said fin stock by severing said fin stock between the side edges of said fin stock, projecting said flange legs inwardly of said tube slot around the front of said tube, and indexing said tube and fin transversely out of the plane of said fln stock to provide space on said tube for repeating the aforesaid operations.

5. A method of forming heat exchange devices which comprises successively forming a plurality of rows of openings transversely across a sheet of fin stock by removing strips of metal from said fin stock inwardly from a point corresponding to the forward edge of a fin to be formed so as to define tube slots approximately of tube width at a front portion of each of said slots and of less than tube width at a rear portion of each of said slots, forming U-shape flanges around said rear portions of said slots with the legs of said flanges extending along the sides of said slots, forming a plurality of equally spaced return bends in a continuous tube to provide a plurality of parallel tube sections with spacing therebetween equal to the spacing of said slots, projecting said sections within the leading slots against the bends of said flanges by relative lateral movement of said fin stock and said tube sections, cutting a fin from said fin stock by severing said fin stock between the front ends of a succeeding row of said tube slots and between said ends and the adjacent edges of said fin stock, projecting said fiange legs of the leading slots inwardly of said tube slots around the front of said tube sections, and indexing said tube and fin transversely out of the plane of said fin stock to provide space on and tube for repeating said fln applying operaons.

6. A method of forming heat exchange devices which comprises forming an opening in a sheet of fin stock by removing a strip of metal from said fln stock inwardly from a point corresponding to the forward edge of a fin to be formed so as to define a tube slot approximately of tube width at a front portion of said slot and of less than tube width at a rear portion of said slot, forming a U-shape flange around said rear portion of said slot with the legs of said flange extending along the sides of said slot, projecting a tube within said slot against the bend of said transversely out of the plane of said :fin stock to provide space on said tube for repeating the aforesaid operations.

7. A method of forming a heat exchange device which comprises forming an opening in a sheet of fin stock by removing a strip of metal from said fin stock inwardly from a point corresponding to the forward edge ofa fin to be formed so as to define a tube slot approximately of tube width at a front portion of said slot and of less than tube width at a rear portion of said slot, forming tool marks rearwardly of the sides of said front portion, said tool marks terminating opposite a center about which said rear portion is formed, forming a U-shape flange around said rear portion of said slot and inwardly of said tool marks with the legs of said flange extending along the sides of said slot, projecting a tube within said slot against the bend of said flange by relative lateral movement of said fin stock and said tube, cutting a fin from said fin stock by severing said fin stock between the side edges of said fln stock, projecting said flange legs inwardly of said tube slot around the front of said tube, and indexing said tube and fin transversely out of the plane of said fin stock to provide space on said tube for repeating the aforesaid operations.

8. A method of forming a heat exchange device which comprises forming an opening in a sheet of fin stock by removing a strip of metal from said fin stock inwardly from a point corresponding to the forward edge of a fin to be formed so as to define a tube slot approximately of tube width at a front portion of said slot and of less than tube width at a rear portion of said slot, slitting said fin stock rearwardly of the sides of said front portion, said slits terminating opposite a center about which said rear portion is formed, forming a U-shape flange around said rear portion of said slot and inwardly of said slits with the legs of said flange extending along the sides of said slot, projecting a tube within said slot against the bend of said flange by relative lateral movement of said fin stock and said tube, cutting a fin from said fin stock by severing said fin stock between the side edges of said fin stock, projecting said flange legs inwardly of said tube slot around the front of said tube, and indexing said tube and fin transversely out of the plane of said fin stock to provide space on said tube for repeating the aforesaid operations.

' JAMES R. HAYWARD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,588,174 Dewald June 8, 1926 '1,599,792 Sage Sept. 14, 1926 1,730,470 Modine Oct. 8, 1929 1,788,068 Scott Jan. 6, 1931 1,884,964 Auld Oct. 25, 1932 1,913,175 Summers June 6, 1933 1,955,837 Scholl Apr. 24, 1934 2,089,340 Cobb Aug. 10, 1937 2,170,774 Fagan Aug. 22, 1939 2,224,550 O'Brien Dec. 10, 1940 2,427,336 Askin Sept. 16, 1947 

